The Tissue Array Shared Resource is new to UCLA. Its goal is to provide a ready resource to researchers in the UCLA community who require in situ tissue-based gene- and protein-level expression studies. The facility is designed to provide flexible and efficient levels of service tailored to any researcher's needs, and includes state-of-the-art arrayers, immunohistochemical and fluorescence in situ hybridization (FISH) capabilities, brightfield and fluorescent microscopes for array analysis, databasing services, and data analysis functionality. Tissue arraying is a technique in which hundreds of tiny (typically 0.6-mm diameter) cylindrical tissue cores are densely and precisely arrayed into a single histologic paraffin block. The resulting tool provides ample material for the analysis of numerous genes in hundreds of individual tumors. The molecular profiles generated are analyzed with a broad spectrum of pathologic, demographic and clinical data, providing a substantive translational link from gene function to clinical meaning. Large-scale investigations such as these are typically outside the realm of resources of individual investigators, and therefore the facility provides: 1) UCLA researchers with ready access to well-characterized and carefully constructed tissue microarrays backed by clinical datasets; 2) flexibility in tailoring individual projects to the exact need of the researcher; 3) consultation and education in the utility, construction, testing and analysis of tissue microarrays; 4) access to full-time research-based pathologists and technicians specifically skilled and richly experienced in all aspects of tissue microarray studies; and 5) a unique resource of increasingly well-characterized molecularly profiled tumor samples. In spite of the short history of the Shared Resource, a number of JCCC members have already utilized the resource, and abundant ongoing studies demonstrate the enthusiasm and widespread utility of this Shared Resource.